8,364 research outputs found
Experimental investigation of feedforward control schemes of a flexible robot manipulator system
This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse
Sensor Fusion Algorithm by Complementary Filter for Attitude Estimation of Quadrotor with Low-Cost IMU
This paper proposes a sensor fusion algorithm by complementary filter technique for attitude estimation of quadrotor UAV using low-cost MEMS IMU. Angular rate from gyroscope tend to drift over a time while accelerometer data is commonly effected with environmental noise. Therefore, high frequency gyroscope signal and low frequency accelerometer signal is fused using complementary filter algorithm. The complementary filter scaling factor K1=0.98 and K2=0.02 are used to merge both gyro and accelerometer. The results show that the smooth roll, pitch and yaw attitude angle can be obtained from the low cost IMU by using proposed sensor fusion algorithm
Mesoporous Functionalized Acid Catalysts And Their Use As Environmentally Friendly Catalysts In Esterification Of Glycerols For Monoglyceride Production.
Monoglycerides are valuable compounds with wide applications as emulsifiers in food, pharmaceutical and cosmetic industries. They can be produced by esterification of glycerols with fatty acids
Sliding mode control for altitude and attitude stabilization of quadrotor UAV with external disturbance
This paper addresses the problem of robust altitude and attitude control of ‘×’ mode configuration quadrotor UAV using Lyapunov stability based sliding mode control with saturation function. The dynamic model of the quadrotor was derived by considering nonlinearity factor. MATLAB Simulink was used to simulate the model in two different conditions; without and with the presence of external disturbance. This was done to test the robustness of the control method. Simulation results showed that the sliding mode controller provides good performance and robustness against disturbance
Velocity control of a unicycle type of mobile robot using optimal pid controller
A unicycle model of control a mobile robot is a simplified modeling approach modified from the differential drive mobile robots. Instead of controlling the right speed, VR and the left speed, VL of the drive systems, the unicycle model is using u and ω as the controller parameters. Tracking is much easier in this model. In this paper, the dynamic of the robot parameter is controlled using two blocks of Proportional-Integral-Derivative(PID) controllers. The gains of the PID are firstly determined using particle swarm optimization(PSO) in offline mode. After the optimal gain is determined, the tracking of the robot’s trajectory is performed online with optimal PID controller. The achieved results of the proposed scheme are compared with those of dynamic model optimized with genetic algorithm(GA) and manually tuned PID controller gains. In the algorithm, the control parameters are computed by minimizing the fitness function defined by using the integral absolute error(IAE) performance index. The simulation results obtained reveal advantages of the proposed PSO-PID dynamic controller for trajectory tracking of a unicycle type of mobile robot. A MATLAB-Simulink program is used to simulate the designed system and the results are graphically plotted. In addition, numerical simulations using 8-shape as a reference trajectory with several numbers of iterations are reported to show the validity of the proposed scheme
Dielectric Function in Highly doped GaN Semiconductor
Inverse of Dielectric Function of highly doped GaN has been calculated by using Lindhard formalism. For simplicity collisional damping, nonparabolicity and the coupling between various electrons and holes were neglected. The inverse of the dielectric function for both Fermi- Dirac and Maxwell Boltzman distribution showed antiscreening peak at small phonon wave vector. On the contrary, both Thomas Fermi and Debye inverse of dielectric function showed screening as expected at same phonon wave vector. There is a sharp growth in the antiscreening peak in the inverse of dielectric function at carrier temperature 77 K and 300K, accompanied with a singularity at carrier concentration greater than . Key words: dielectric function, GaN and screened optical phonon scattering rat
Negative imaginary theorem with an application to robust control of a crane system
This paper presents an integral sliding mode (ISM) control for a case of negative imaginary (NI) systems. A gantry crane system (GCS) is considered in this work. ISM is a nonlinear control method introducing significant properties of precision, robustness, stress-free tuning and implementation. The GCS model considered in this work is derived based on the x direction and sway motion of the payload. The GCS is a negative imaginary (NI) system with a single pole at the origin. ISM consist of two blocks; the inner block made up of a pole placement controller (NI controller), designed using linear matrix inequality for robustness and outer block made up of sliding mode control to reject disturbances. The ISM is designed to control position tracking and anti-swing payload motion. The robustness of the control scheme is tested with an input disturbance of a sine wave signal. The simulation results show the effectiveness of the control scheme
Potentiometric Determination of Ketotifen Fumarate in Pharmaceutical Preparations and Urine Using Carbon Paste and PVC Membrane Selective Electrodes
This study compares
between unmodified carbon paste (CPE; the paste
has no ion pair) and polyvinyl chloride (PVC)
membrane selective electrodes that were used in
potentiometric determination of ketotifen
fumarate (KTF), where sodium tetraphenylborate
(NaTPB) was used as titrant. The performance
characteristics of these sensors were evaluated
according to IUPAC recommendations which reveal
a fast, stable, and linear response for KTF over
the concentration range of 10−7 to
10−2 mol L−1. The
electrodes show Nernstian slope value of
52.51 ± 0.20 and 51.51 ± 0.25 mV decade−1 for CPE and PVC membrane
electrodes at 30°C, respectively. The potential
is nearly stable over the pH range 3.0–6.0 and 2.0–7.0
for CPE and PVC membrane electrodes, respectively. Selectivity
coefficient values towards different inorganic cations, sugars, and
amino acids reflect high selectivity of the prepared electrodes.
The electrodes responses at different temperatures were also
studied, and long operational lifetime of 12 and 5 weeks for CPE
and PVC membrane electrodes, respectively, were found. These are
used for determination of ketotifen fumarate using potentiometric
titration, calibration, and standard addition methods in pure
samples, its pharmaceutical preparations (Zaditen tablets), and
biological fluid (urine). The direct potentiometric determination
of KTF using the proposed sensors gave recoveries % of 98.97 ± 0.53 and 98.62 ± 0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method
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